birth name, new name definitely.
Possibly date changed? I know there's no "I'm a girl today and a boy yesterday" date, at least a year possibly? So that there is a age estimate when they transitioned.
birth gender?
We have a family member that transitioned and I would like the tree to represent both the information that they were born with, as well as the current information. I see it little different that a maiden name or ex-wife/husband.